Conventionally, an electronic device that includes semiconductor devices and the like are known in which after contact points are connected by wire bonding, in order to secure moisture resistance of the contact points having been subject to the wire bonding, a case accommodating a semiconductor device is filled with a gelatinous synthetic resin, such that contact point portions are covered by the synthetic resin. As for this structure, it has been pointed out that if the filled synthetic resin vibrates, the vibration might be transferred to wires, resulting in breaking of the wires. For this reason, methods of preventing vibration of wires by reducing an amount of filled synthetic resin in the above-mentioned structure have been proposed (for example, see Patent Document 1). Patent Document 1 discloses a method which puts a power device having a metal wire connected thereto by wire bonding in a case, injects Silicone Resin into the case from above, inserts a suction nozzle into the case, and sucks the Silicone Resin until a required height is obtained.
However, in the method disclosed in Patent Document 1, since a process for sucking the injected Silicone Resin is newly added, there is a concern that a manufacturing lead time for electronic devices might extend and a manufacturing cost might increase due to investment in suction equipment. Also, for example, in a high-current power device, metal wires are disposed at high density. Therefore, if the above-mentioned method is applied to that device, it is required to secure a space for inserting the suction nozzle while avoiding wires, and thus there is a concern that the areas of electronic devices might increase and the sizes of products might increase. Further, in a case of suppressing an amount of synthetic resin as disclosed Patent Document 1, although vibration is not transferred to wires, the wires may not be covered by the synthetic resin. For example, in a power device, since wires are disposed at high density, in order to prevent neighboring wires from being short-circuited, it is preferable to cover the wires with a synthetic resin. Even in other electronic devices, it is important to secure the corrosion resistance of wires and prevent wires and other components, or wires from being short-circuited. Therefore, covered wires are very advantageous.